Subscriber&#39;s telephone-circuit.



H. M. POST.

SUBSCRIBERS TELEPHONE CIRCUIT, APFLIQATION FILED JULY 31, 1905.

901338,; Patented 001;.20, 1908..

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Phone-.Qircuitxe, Of WhlGh t-hB' following is a pe fige iml I .s Myi, iiyeuti -elat"e to subscribers circuitsfudapted forusesin connection with cener y;teleph esx t s- In systemsipf, heahgyka class where a principal source of-energy;-iS..-located at the central adapted tofurnish current for signaling purposes between the central office and substa n ;endsta u i 1 for actuating the. substation transmitters, it has been {thund undesirable-, for various wellkngWn reasus,-:to locate the telephone re ceiver at thensubsjtatign in the. path of; the eurren'tsfron the central-etfice for actuating the: substation transmitter.

It has been customary in some cases to locate the receiyer in a:conductiyely'isolated circuit from-the ath of clirect current to the transmitter; sai isolated circuit. being: in ductiy elly connectedwith said direct current path mcan of induction-coil; the wind mgs o the receiver in such case only being traversed by the high, frequency voice currentsjglthas also been ,groposed' to rovide meansj suchfasilanlimpe ance coil w ich is p ue-e a t e ae sa saef t high. qu y voice currents ,inthep'ath.of direct current from the central office and to provide-a shunt P h a dis di pde e l in w h h receiveris located, said: shunt path containing'a ccndenseroi'othermeans for rendering;

saldpath opaque tQ-tlie, passage of direct cur- 1 rent; By, this anangemen't' two paths are Erovid'ed; one opaquegto ithe voiceccurrents Ht} ii sper t qrfl 'fififi .w e ten t o e 'cpaquitb he ei sa f d rect cu but? .transjgariit to" ceiverfl invention-relates to this secondmentioned inethndof -preventing the direct current'r'romithe' cent idl'jofiice from -'travers ingztheiboils Qfthereceiyen Such a circuit es i iwd n claimed Let-tersTP-atent' cf \illiam il Z Dean, Alfie; 122,212fiissiied March 10; 1903; I pro 'se'flto locate. the usual polarized, ringer, e windingsofiwhich preferablyhave;

(impair-may low-resistance; in sriesswith enerically e high frequency oice currents; said .1 latter path contin ing; the re;

-The arrangemen? is such: that whenthe 1e ringer is in the path of direct current frdin thc --compa'nying drawing, in which:

' tory results in practice.

a condenser in a normally-closed: bridge of the line conductors, so that with the receiver upon its book the ringer Will-be in the-pathbfsignaling current" from the centralstation ceiver removed from its hook the'condensen is connected in" series-with the receiver in a shunt path of the coils of the windings of I said ringer, so that during'conversation the central station, the-coils-of theringer msgnet' possessing suflicient impedance to prevent the passage of the voice currentsovercsaid path to an appreciable degree, the voice-cuiz-r rents beingadapted to traverse the path'on-t tainhlgrthe receiver'and condenser i11 shuntof the pathcontaining the ringer magnet. a

1 have illustrated my inventioninthe ac- Figure 1 isc-a diagram ofa circuit arrangement illustrating .the-principle of my inven 2-. tion and-Fig. 2 shows-the preferred arrangement ofthe contactsiadapted:tube-actuated by the removal 0b the receiver from-the switch hook. g

My invention isadaptedfor use-width any central. energy telephonesystemand as the operation of suchsyst'ems is wellunde-rstodd-I. have not deemedit neoessary'to showthe cam-- tral station equipment of such a system as my invention cambe clearly understood by illus tratingthe subscriber s station and indicating the limbs 1 and-2 of the telephone'line extending-t0 the central 'ofiice. I preferably provide an ordinary polarized ringer'3, the coils ofisaid ringer preferably being ofidomparatively low ohmic resistance, a resistancegoffrom- 75 to ohms'having been-found't'o 'give-satisfam c nected in abridge of the; line-conductors: 1' and 2 by means of'conductors-4;,,5 and 6; said 7 bridge containing a condenser 7 and being normally closed at contactpoint-8-by means of the switch hook-9iwhenthe receiv er 10iis not use. A. nonnal-ly closed path' for sig:- 100 naling current is thus provided, which contains only the coils of theiringei: 3- and the condenser 7 Wlh'em the receiyerisiiemoved from-the switch hook said'hook' is ad apted to break the; circuit of the bell 3 at the-contact ggcint .SJand to engage .the contactpoint 1'1, a the receiyer -10 being connected' between said .contafc t.poi n t. 1 1; and the line conduc orll iy ismrieaty the switch hook, catamaransm The" ringer is-ccn insulated thcrefrbnnis adapted to form clectrical connection with the contact point 14- When the receiver is removed from its hook, thus completing" a path for direct current through the transmitter 15, A conductor 16 connects the contact point 14 with the conductor and a conductor 17 containing the transmit er extends from the limb 2 of the tele hone line tothe contact 13 carried. by" the 'ook switch. p The circuits are shown with the receiver upon the hook and'the apparatus in COIldl: tion to receive a call from the central o'ffice. Assuming that a .call is sent to the subscrib "ers station represented in. Fig. 1, the. signalingcui'rent from the central office may be traced over the following: path-z line conductorl, conductorf4, coils ofithe ringer 3', conductor 5, condenser '7, switch hook and. fgiliktact point'S, and condenser 6 to'the other ing the receiver 10 from'its hook a circuit willbe closed for directcurrent'from the'central office over the following path: line conductor '1, conductor 4, the coils of the ringer'3, con tductors 5 and 16,- contact 'o'int Mend con-- tact 1-3, and conductor-17 t ough the trans mitter 15 to the other limb 2 of the tele hone line; A ath for the .voice currents w 1 also be close from limb 1 of the telephone line over conductor 12 including the coils of the from its hook for closing a path for direct cur- V "dance to prevent t e passage of voice currents, of the telephone line Upon remov-- for preventing the receiver 10, contact point 11, hook switch 9, condenser 7, conductor 16, contacts'14 and '13 and conductor 17, including the transmitter 1 be'noted that by the removal of the receiver from its hook the path for -ringing'current is broken at contact point 8 andcondenser 7 which was in said path is included in the path --for voice currents which is closed at contact points 11 and "14, said .path, due tothe pres- -ence of the condenser, being opaque to the passage of direct current. .The coils of the. ringer, as previously stated, possess sufficient impedance toiprevent the passage of voice currentsto an a preciable degree, but permit the passage 0 direct current for the -actu-' ation of the transmitter 15. The coils of the 1 er thus serve the double function of sigto hahng the substation and shunting the voice currents through the pathcpntaimng the receiver'and the condenser T-during conversation; Y It will-be understood that other circuit arrangem'ents may be provided without depart ing from the spirit of my invention, the details in the arrangement here shown not be-. ing essential, and I do not wish to; limit my self to the circuit arrangement shown further than is described in the appendedclaimsz' l. A subscribers telephone circult coinprising'apath for signaling-current contamthe coils of a suitable ringer,'a pathfor 15to the limb 2 of thetelephone line. It will 'wi'th both of said at'hs, the coils of said in vent t e passage'of voice currents, said condenser preventmg the passage of direct cur- ,rent through the path containing the re 'ceiver', substantially as described. 5. -A subscriber's telephone circuit com prising two paths for current, one of said currents containing the ceilsof'a restantially" as described.

2; A-subscribers; telephone circuit com- 7.5 prising a path for signaling current containing. the coils of 'a.suitable ringer, a path for talking currents containing the coils of a receiver", means when the receiver is removed rent-through the coilsof saidringer and for connecting both said. ringer coils and said receivercoils in series with "the transmitter; saidringer coils ossessing. sufl'icient impeand means in the path containing the receiver assag' of direct current. 3. -A- subscriber s-tele hone circuit comprising-two paths forgcurrent, one of said paths being-opaque to direct currents and containing a receiver and a -condenser, the other of'said pathscontaining the coils of a ringer and being opaque o voice currents, a transmitter m series wit both paths, and switching means under the control of the subscriber for placing saidcondenser and ringer coils in series in the telephone'line, and for excludingsaid transmitter from the line circu-it,' substantially as'describe p .4. A subscribers telephone circuit comprising-a path for signaling current containmg the oils of a suitable ringer and a condenser, a normally-open path for talking currents. containing the coils of a receiver, means when the receiver is removed from its hook for closing a path. for direct current through. the coils'of said ringer, and for including said, condenser in the "path containing the re ceiver and for placing a transmitter in series ssessing' su cient impedance to pre-- paths containing a receiver and a condenser mseries, theother of said paths containing the coils of a ringer, a transmitter in series with both paths, and means for placing said condenser and ringer in series 1n thetelephone line, substantiall Y as described.

6. A subs'c'riberste ephone circuit comprising 'a path for signaling current containmg. the coils of a suitable ringer, a path for talking currents containing the coils of a re-' ceiver, means when the receiver is removed from its hook for closing a path for direct. current through the coils of said ringer, said 1330 cient impedance to vent the passage of voice currents, means in the path containing the receiver for prevent- ,ing the passage of direct current, and, a transmitter in the path of direct current through the coils of said ringer and in the path of the talking currents through the coils of said re ceiver.

7. A- subscribers telephone circuit comprising the coils of a suitable ringer and a condenser, in a normally-closed path for sig naling current, a receiver in a normally-open path for voice currents, a transmitter and means when the receiver is removed from its hook for connecting the coils of said ringer in series with said transmitter and in the path of direct current, and for connecting said condenser in series with the receiver and the transmitter and in the path of talking currents, the coils of said ringer possessing sufiiprevent the passage of the talking currents. I

S; A subscribers telephone circuit comprising two paths for current, one ofsaid paths being adapted to pass voice currents and not direct currents and containing a receiver, and the other path being adapted to pass direct currents and not voice currents and containing the coils of a ringer, a transmitter in series with both of said paths and means for placing said ringer coils in series with a portion of said former pat-h, whereby actuating current may be sent through the ringer coils to produce a signal at the substa tion, but whereby direct current cannot flow therethrough to produce a signal at the central office, substantially as described.

9. A subscribers telephone circuit having a condenser and the coils of a ringer normally in series in the telephone line circuit. for signaling purposes, of a hook switch adapted by its operation to place said condenser and said ringer coils in parallel in said telephone line and in serieswith a transmitter for talking purposes, substantially as described.

10. In a su'bscribers telephone circuit, the combination with a switching mechanism, of

a condenser, a receiver and a ringer electrically associated therewith, means under one condition 'of said switching mechanism for connecting said condenser and ringer in series in the telephone line and excluding said receiver therefrom, and in the other condition of said switching mechanism for connecting said receiver and condenser in series and in parallel with said ringer, and a transmitter in series with both said receiver and said ringer, substantially as described.

- 11. In asuhscribers telephone circuit, the combination with a path for direct currents containing the coils of a ringer, of a path. for voice currents in arallel with said first path containing the coi s of a receiver, and a transmitter in series with each of said paths, substantially as described. 1

12. In a subscribers telephone circuit, the combination of a transmitter and ringer in a bridge of the telephone line, and a condenser and receiver in parallel with the ringer and in series Withthe transmitter, substantially asdescribed.

13. In a subscriber s telephone circuit, the combination of a condenser and a ringer in a normally closed shunt of the limbs of the telephone line, a receiver, a transmitter and switching mechanism adapted to connect said receiver and condenser in parallel with the ringer and in series with said transmitter, substantially as described.

Signed by me at Chicago, county of Cook and State of Illinois, in the presence of two witnesses.

I HOWARD M. POST. 

